package com.util;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;

public class EncodingFilter
  implements Filter
{
  protected String encoding = null;

  protected FilterConfig filterConfig = null;

  public void destroy() {
    this.encoding = null;
    this.filterConfig = null;
  }

  public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
    throws IOException, ServletException
  {
    String encoding = selectEncoding(request);
    if (encoding != null) {
      request.setCharacterEncoding(encoding);
      response.setCharacterEncoding(encoding);
    }

    chain.doFilter(request, response);
  }

  public void init(FilterConfig filterConfig) throws ServletException {
    this.filterConfig = filterConfig;
    this.encoding = filterConfig.getInitParameter("encoding");
  }

  protected String selectEncoding(ServletRequest request) {
    return this.encoding;
  }
}